The present invention generally relates to a temperature responsive expansion value and, more particularly, to an expansion valve of the type which is furnished with a mechanism to make up for a drop in the condensation pressure attributable to that in the atmospheric temperature in wintertime and thereby control the amount of refrigerant supply to a predetermined constant amount for a given superheating degree.
In a refrigeration system, pressure at the evaporator remains substantially at a constant level without being affected very much by atmospheric temperature which may vary greatly between summertime and wintertime for instance. However, pressure at the condenser undergoes a significant variation in relation to the condensation temperature. Particularly in an air cooled condenser, it is known to build up a pressure in summertime which is several times the pressure in wintertime due to the difference in atmospheric temperature. Supposing that an expansion valve incorporated in the refrigeration system maintains a given opening degree, a larger difference in pressure permits a larger amount of refrigerant to flow therethrough. It will therefore be seen that, with a specific expansion valve designed to suit its operation in summertime for example, the amount of fluid flow allowed therethrough will become short in wintertime when the atmospheric temperature is generally far lower than in summertime even though the opening degree of the valve may be the largest which corresponds to a predetermined maximum superheating degree.